include/net/ip.h

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Definitions for the IP module.
   7  *
   8  * Version:     @(#)ip.h        1.0.2   05/07/93
   9  *
  10  * Authors:     Ross Biro
  11  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12  *              Alan Cox, <gw4pts@gw4pts.ampr.org>
  13  *
  14  * Changes:
  15  *              Mike McLagan    :       Routing by source
  16  *
  17  *              This program is free software; you can redistribute it and/or
  18  *              modify it under the terms of the GNU General Public License
  19  *              as published by the Free Software Foundation; either version
  20  *              2 of the License, or (at your option) any later version.
  21  */
  22 #ifndef _IP_H
  23 #define _IP_H
  24
  25 #include <linux/types.h>
  26 #include <linux/ip.h>
  27 #include <linux/in.h>
  28 #include <linux/skbuff.h>
  29
  30 #include <net/inet_sock.h>
  31 #include <net/snmp.h>
  32
  33 struct sock;
  34
  35 struct inet_skb_parm
  36 {
  37         struct ip_options       opt;            /* Compiled IP options          */
  38         unsigned char           flags;
  39
  40 #define IPSKB_FORWARDED         1
  41 #define IPSKB_XFRM_TUNNEL_SIZE  2
  42 #define IPSKB_XFRM_TRANSFORMED  4
  43 #define IPSKB_FRAG_COMPLETE     8
  44 #define IPSKB_REROUTED          16
  45 };
  46
  47 static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
  48 {
  49         return ip_hdr(skb)->ihl * 4;
  50 }
  51
  52 struct ipcm_cookie
  53 {
  54         __be32                  addr;
  55         int                     oif;
  56         struct ip_options       *opt;
  57 };
  58
  59 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
  60
  61 struct ip_ra_chain
  62 {
  63         struct ip_ra_chain      *next;
  64         struct sock             *sk;
  65         void                    (*destructor)(struct sock *);
  66 };
  67
  68 extern struct ip_ra_chain *ip_ra_chain;
  69 extern rwlock_t ip_ra_lock;
  70
  71 /* IP flags. */
  72 #define IP_CE           0x8000          /* Flag: "Congestion"           */
  73 #define IP_DF           0x4000          /* Flag: "Don't Fragment"       */
  74 #define IP_MF           0x2000          /* Flag: "More Fragments"       */
  75 #define IP_OFFSET       0x1FFF          /* "Fragment Offset" part       */
  76
  77 #define IP_FRAG_TIME    (30 * HZ)               /* fragment lifetime    */
  78
  79 struct msghdr;
  80 struct net_device;
  81 struct packet_type;
  82 struct rtable;
  83 struct sockaddr;
  84
  85 extern int              igmp_mc_proc_init(void);
  86
  87 /*
  88  *      Functions provided by ip.c
  89  */
  90
  91 extern int              ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
  92                                               __be32 saddr, __be32 daddr,
  93                                               struct ip_options *opt);
  94 extern int              ip_rcv(struct sk_buff *skb, struct net_device *dev,
  95                                struct packet_type *pt, struct net_device *orig_dev);
  96 extern int              ip_local_deliver(struct sk_buff *skb);
  97 extern int              ip_mr_input(struct sk_buff *skb);
  98 extern int              ip_output(struct sk_buff *skb);
  99 extern int              ip_mc_output(struct sk_buff *skb);
 100 extern int              ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *));
 101 extern int              ip_do_nat(struct sk_buff *skb);
 102 extern void             ip_send_check(struct iphdr *ip);
 103 extern int              __ip_local_out(struct sk_buff *skb);
 104 extern int              ip_local_out(struct sk_buff *skb);
 105 extern int              ip_queue_xmit(struct sk_buff *skb, int ipfragok);
 106 extern void             ip_init(void);
 107 extern int              ip_append_data(struct sock *sk,
 108                                        int getfrag(void *from, char *to, int offset, int len,
 109                                                    int odd, struct sk_buff *skb),
 110                                 void *from, int len, int protolen,
 111                                 struct ipcm_cookie *ipc,
 112                                 struct rtable *rt,
 113                                 unsigned int flags);
 114 extern int              ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb);
 115 extern ssize_t          ip_append_page(struct sock *sk, struct page *page,
 116                                 int offset, size_t size, int flags);
 117 extern int              ip_push_pending_frames(struct sock *sk);
 118 extern void             ip_flush_pending_frames(struct sock *sk);
 119
 120 /* datagram.c */
 121 extern int              ip4_datagram_connect(struct sock *sk,
 122                                              struct sockaddr *uaddr, int addr_len);
 123
 124 /*
 125  *      Map a multicast IP onto multicast MAC for type Token Ring.
 126  *      This conforms to RFC1469 Option 2 Multicasting i.e.
 127  *      using a functional address to transmit / receive
 128  *      multicast packets.
 129  */
 130
 131 static inline void ip_tr_mc_map(__be32 addr, char *buf)
 132 {
 133         buf[0]=0xC0;
 134         buf[1]=0x00;
 135         buf[2]=0x00;
 136         buf[3]=0x04;
 137         buf[4]=0x00;
 138         buf[5]=0x00;
 139 }
 140
 141 struct ip_reply_arg {
 142         struct kvec iov[1];
 143         int         flags;
 144         __wsum      csum;
 145         int         csumoffset; /* u16 offset of csum in iov[0].iov_base */
 146                                 /* -1 if not needed */
 147         int         bound_dev_if;
 148 };
 149
 150 #define IP_REPLY_ARG_NOSRCCHECK 1
 151
 152 void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg,
 153                    unsigned int len);
 154
 155 struct ipv4_config
 156 {
 157         int     log_martians;
 158         int     no_pmtu_disc;
 159 };
 160
 161 extern struct ipv4_config ipv4_config;
 162 #define IP_INC_STATS(net, field)        SNMP_INC_STATS((net)->mib.ip_statistics, field)
 163 #define IP_INC_STATS_BH(net, field)     SNMP_INC_STATS_BH((net)->mib.ip_statistics, field)
 164 #define IP_ADD_STATS_BH(net, field, val) SNMP_ADD_STATS_BH((net)->mib.ip_statistics, field, val)
 165 #define NET_INC_STATS(net, field)       SNMP_INC_STATS((net)->mib.net_statistics, field)
 166 #define NET_INC_STATS_BH(net, field)    SNMP_INC_STATS_BH((net)->mib.net_statistics, field)
 167 #define NET_INC_STATS_USER(net, field)  SNMP_INC_STATS_USER((net)->mib.net_statistics, field)
 168 #define NET_ADD_STATS_BH(net, field, adnd) SNMP_ADD_STATS_BH((net)->mib.net_statistics, field, adnd)
 169 #define NET_ADD_STATS_USER(net, field, adnd) SNMP_ADD_STATS_USER((net)->mib.net_statistics, field, adnd)
 170
 171 extern unsigned long snmp_fold_field(void *mib[], int offt);
 172 extern int snmp_mib_init(void *ptr[2], size_t mibsize);
 173 extern void snmp_mib_free(void *ptr[2]);
 174
 175 extern void inet_get_local_port_range(int *low, int *high);
 176
 177 extern int sysctl_ip_default_ttl;
 178 extern int sysctl_ip_nonlocal_bind;
 179
 180 extern struct ctl_path net_ipv4_ctl_path[];
 181
 182 /* From inetpeer.c */
 183 extern int inet_peer_threshold;
 184 extern int inet_peer_minttl;
 185 extern int inet_peer_maxttl;
 186 extern int inet_peer_gc_mintime;
 187 extern int inet_peer_gc_maxtime;
 188
 189 /* From ip_output.c */
 190 extern int sysctl_ip_dynaddr;
 191
 192 extern void ipfrag_init(void);
 193
 194 extern void ip_static_sysctl_init(void);
 195
 196 #ifdef CONFIG_INET
 197 #include <net/dst.h>
 198
 199 /* The function in 2.2 was invalid, producing wrong result for
 200  * check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
 201 static inline
 202 int ip_decrease_ttl(struct iphdr *iph)
 203 {
 204         u32 check = (__force u32)iph->check;
 205         check += (__force u32)htons(0x0100);
 206         iph->check = (__force __sum16)(check + (check>=0xFFFF));
 207         return --iph->ttl;
 208 }
 209
 210 static inline
 211 int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 212 {
 213         return (inet_sk(sk)->pmtudisc == IP_PMTUDISC_DO ||
 214                 (inet_sk(sk)->pmtudisc == IP_PMTUDISC_WANT &&
 215                  !(dst_metric_locked(dst, RTAX_MTU))));
 216 }
 217
 218 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 219
 220 static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
 221 {
 222         if (iph->frag_off & htons(IP_DF)) {
 223                 /* This is only to work around buggy Windows95/2000
 224                  * VJ compression implementations.  If the ID field
 225                  * does not change, they drop every other packet in
 226                  * a TCP stream using header compression.
 227                  */
 228                 iph->id = (sk && inet_sk(sk)->daddr) ?
 229                                         htons(inet_sk(sk)->id++) : 0;
 230         } else
 231                 __ip_select_ident(iph, dst, 0);
 232 }
 233
 234 static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
 235 {
 236         if (iph->frag_off & htons(IP_DF)) {
 237                 if (sk && inet_sk(sk)->daddr) {
 238                         iph->id = htons(inet_sk(sk)->id);
 239                         inet_sk(sk)->id += 1 + more;
 240                 } else
 241                         iph->id = 0;
 242         } else
 243                 __ip_select_ident(iph, dst, more);
 244 }
 245
 246 /*
 247  *      Map a multicast IP onto multicast MAC for type ethernet.
 248  */
 249
 250 static inline void ip_eth_mc_map(__be32 naddr, char *buf)
 251 {
 252         __u32 addr=ntohl(naddr);
 253         buf[0]=0x01;
 254         buf[1]=0x00;
 255         buf[2]=0x5e;
 256         buf[5]=addr&0xFF;
 257         addr>>=8;
 258         buf[4]=addr&0xFF;
 259         addr>>=8;
 260         buf[3]=addr&0x7F;
 261 }
 262
 263 /*
 264  *      Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
 265  *      Leave P_Key as 0 to be filled in by driver.
 266  */
 267
 268 static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
 269 {
 270         __u32 addr;
 271         unsigned char scope = broadcast[5] & 0xF;
 272
 273         buf[0]  = 0;            /* Reserved */
 274         buf[1]  = 0xff;         /* Multicast QPN */
 275         buf[2]  = 0xff;
 276         buf[3]  = 0xff;
 277         addr    = ntohl(naddr);
 278         buf[4]  = 0xff;
 279         buf[5]  = 0x10 | scope; /* scope from broadcast address */
 280         buf[6]  = 0x40;         /* IPv4 signature */
 281         buf[7]  = 0x1b;
 282         buf[8]  = broadcast[8];         /* P_Key */
 283         buf[9]  = broadcast[9];
 284         buf[10] = 0;
 285         buf[11] = 0;
 286         buf[12] = 0;
 287         buf[13] = 0;
 288         buf[14] = 0;
 289         buf[15] = 0;
 290         buf[19] = addr & 0xff;
 291         addr  >>= 8;
 292         buf[18] = addr & 0xff;
 293         addr  >>= 8;
 294         buf[17] = addr & 0xff;
 295         addr  >>= 8;
 296         buf[16] = addr & 0x0f;
 297 }
 298
 299 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 300 #include <linux/ipv6.h>
 301 #endif
 302
 303 static __inline__ void inet_reset_saddr(struct sock *sk)
 304 {
 305         inet_sk(sk)->rcv_saddr = inet_sk(sk)->saddr = 0;
 306 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 307         if (sk->sk_family == PF_INET6) {
 308                 struct ipv6_pinfo *np = inet6_sk(sk);
 309
 310                 memset(&np->saddr, 0, sizeof(np->saddr));
 311                 memset(&np->rcv_saddr, 0, sizeof(np->rcv_saddr));
 312         }
 313 #endif
 314 }
 315
 316 #endif
 317
 318 extern int      ip_call_ra_chain(struct sk_buff *skb);
 319
 320 /*
 321  *      Functions provided by ip_fragment.c
 322  */
 323
 324 enum ip_defrag_users
 325 {
 326         IP_DEFRAG_LOCAL_DELIVER,
 327         IP_DEFRAG_CALL_RA_CHAIN,
 328         IP_DEFRAG_CONNTRACK_IN,
 329         IP_DEFRAG_CONNTRACK_OUT,
 330         IP_DEFRAG_VS_IN,
 331         IP_DEFRAG_VS_OUT,
 332         IP_DEFRAG_VS_FWD
 333 };
 334
 335 int ip_defrag(struct sk_buff *skb, u32 user);
 336 int ip_frag_mem(struct net *net);
 337 int ip_frag_nqueues(struct net *net);
 338
 339 /*
 340  *      Functions provided by ip_forward.c
 341  */
 342
 343 extern int ip_forward(struct sk_buff *skb);
 344
 345 /*
 346  *      Functions provided by ip_options.c
 347  */
 348
 349 extern void ip_options_build(struct sk_buff *skb, struct ip_options *opt, __be32 daddr, struct rtable *rt, int is_frag);
 350 extern int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb);
 351 extern void ip_options_fragment(struct sk_buff *skb);
 352 extern int ip_options_compile(struct net *net,
 353                               struct ip_options *opt, struct sk_buff *skb);
 354 extern int ip_options_get(struct net *net, struct ip_options **optp,
 355                           unsigned char *data, int optlen);
 356 extern int ip_options_get_from_user(struct net *net, struct ip_options **optp,
 357                                     unsigned char __user *data, int optlen);
 358 extern void ip_options_undo(struct ip_options * opt);
 359 extern void ip_forward_options(struct sk_buff *skb);
 360 extern int ip_options_rcv_srr(struct sk_buff *skb);
 361
 362 /*
 363  *      Functions provided by ip_sockglue.c
 364  */
 365
 366 extern void     ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb);
 367 extern int      ip_cmsg_send(struct net *net,
 368                              struct msghdr *msg, struct ipcm_cookie *ipc);
 369 extern int      ip_setsockopt(struct sock *sk, int level, int optname, char __user *optval, int optlen);
 370 extern int      ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen);
 371 extern int      compat_ip_setsockopt(struct sock *sk, int level,
 372                         int optname, char __user *optval, int optlen);
 373 extern int      compat_ip_getsockopt(struct sock *sk, int level,
 374                         int optname, char __user *optval, int __user *optlen);
 375 extern int      ip_ra_control(struct sock *sk, unsigned char on, void (*destructor)(struct sock *));
 376
 377 extern int      ip_recv_error(struct sock *sk, struct msghdr *msg, int len);
 378 extern void     ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 379                               __be16 port, u32 info, u8 *payload);
 380 extern void     ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
 381                                u32 info);
 382
 383 /* sysctl helpers - any sysctl which holds a value that ends up being
 384  * fed into the routing cache should use these handlers.
 385  */
 386 int ipv4_doint_and_flush(ctl_table *ctl, int write,
 387                          struct file* filp, void __user *buffer,
 388                          size_t *lenp, loff_t *ppos);
 389 int ipv4_doint_and_flush_strategy(ctl_table *table, int __user *name, int nlen,
 390                                   void __user *oldval, size_t __user *oldlenp,
 391                                   void __user *newval, size_t newlen);
 392 #ifdef CONFIG_PROC_FS
 393 extern int ip_misc_proc_init(void);
 394 #endif
 395
 396 #endif  /* _IP_H */